u-boot/board/svm_sc8xx/flash.c

/*
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>
#include <mpc8xx.h>

#ifndef	CONFIG_ENV_ADDR
#define CONFIG_ENV_ADDR	(CONFIG_SYS_FLASH_BASE + CONFIG_ENV_OFFSET)
#endif

flash_info_t	flash_info[CONFIG_SYS_MAX_FLASH_BANKS]; /* info for FLASH chips	*/

/*-----------------------------------------------------------------------
 * Functions
 */
static int write_word (flash_info_t *info, ulong dest, ulong data);
#if 0
static ulong flash_get_size (vu_long *addr, flash_info_t *info);
static void flash_get_offsets (ulong base, flash_info_t *info);
#endif
#ifdef  CONFIG_BOOT_8B
static int my_in_8( unsigned char *addr);
static  void my_out_8( unsigned char *addr, int val);
#endif
#ifdef  CONFIG_BOOT_16B
static  int my_in_be16( unsigned short *addr);
static  void my_out_be16( unsigned short *addr, int val);
#endif
#ifdef  CONFIG_BOOT_32B
static  unsigned my_in_be32( unsigned *addr);
static  void my_out_be32( unsigned *addr, int val);
#endif
/*-----------------------------------------------------------------------
 */

unsigned long flash_init (void)
{
	volatile immap_t     *immap  = (immap_t *)CONFIG_SYS_IMMR;
	volatile memctl8xx_t *memctl = &immap->im_memctl;
	unsigned long size_b0, size_b1;
	int i;

	size_b0=0;
	size_b1=0;
	/* Init: no FLASHes known */
	for (i=0; i<CONFIG_SYS_MAX_FLASH_BANKS; ++i) {
		flash_info[i].flash_id = FLASH_UNKNOWN;
	}
#ifdef CONFIG_SYS_DOC_BASE
#ifndef CONFIG_FEL8xx_AT
	memctl->memc_or5 = (0xffff8000 | CONFIG_SYS_OR_TIMING_DOC ); /* 32k bytes */
	memctl->memc_br5 = CONFIG_SYS_DOC_BASE | 0x401;
#else
	memctl->memc_or3 = (0xffff8000 | CONFIG_SYS_OR_TIMING_DOC ); /* 32k bytes */
	memctl->memc_br3 = CONFIG_SYS_DOC_BASE | 0x401;
#endif
#endif
#if defined( CONFIG_BOOT_8B)
/*        memctl->memc_or0 = 0xfff80ff4; /###* 4MB bytes */
/*        memctl->memc_br0 = 0x40000401; */
	size_b0 = 0x80000;  /* 512 K */
	flash_info[0].flash_id = FLASH_MAN_AMD | FLASH_AM040;
	flash_info[0].sector_count = 8;
	flash_info[0].size = 0x00080000;
	/* set up sector start address table */
	for (i = 0; i < flash_info[0].sector_count; i++)
	flash_info[0].start[i] = 0x40000000 + (i * 0x10000);
	/* protect all sectors */
	for (i = 0; i < flash_info[0].sector_count; i++)
	flash_info[0].protect[i] = 0x1;
#elif defined (CONFIG_BOOT_16B)
/*        memctl->memc_or0 = 0xfff80ff4; /###* 4MB bytes */
/*        memctl->memc_br0 = 0x40000401; */
	size_b0 = 0x400000;  /* 4MB , assume AMD29LV320B */
	flash_info[0].flash_id = FLASH_MAN_AMD | FLASH_AM320B;
	flash_info[0].sector_count = 67;
	flash_info[0].size = 0x00400000;
	/* set up sector start address table */
	flash_info[0].start[0] = 0x40000000  ;
	flash_info[0].start[1] = 0x40000000 + 0x4000;
	flash_info[0].start[2] = 0x40000000 + 0x6000;
	flash_info[0].start[3] = 0x40000000 + 0x8000;
	for (i = 4; i < flash_info[0].sector_count; i++)
	flash_info[0].start[i] = 0x40000000 + 0x10000 + ((i-4) * 0x10000);
	/* protect all sectors */
	for (i = 0; i < flash_info[0].sector_count; i++)
	flash_info[0].protect[i] = 0x1;
#endif


#ifdef CONFIG_BOOT_32B

	/* Static FLASH Bank configuration here - FIXME XXX */

	size_b0 = flash_get_size((vu_long *)FLASH_BASE0_PRELIM, &flash_info[0]);

	if (flash_info[0].flash_id == FLASH_UNKNOWN) {
		printf ("## Unknown FLASH on Bank 0 - Size = 0x%08lx = %ld MB\n",
			size_b0, size_b0<<20);
	}

	size_b1 = flash_get_size((vu_long *)FLASH_BASE1_PRELIM, &flash_info[1]);

	if (size_b1 > size_b0) {
		printf ("## ERROR: "
			"Bank 1 (0x%08lx = %ld MB) > Bank 0 (0x%08lx = %ld MB)\n",
			size_b1, size_b1<<20,
			size_b0, size_b0<<20
		);
		flash_info[0].flash_id	= FLASH_UNKNOWN;
		flash_info[1].flash_id	= FLASH_UNKNOWN;
		flash_info[0].sector_count	= -1;
		flash_info[1].sector_count	= -1;
		flash_info[0].size		= 0;
		flash_info[1].size		= 0;
		return (0);
	}

	/* Remap FLASH according to real size */
	memctl->memc_or0 = CONFIG_SYS_OR_TIMING_FLASH | (-size_b0 & OR_AM_MSK);
	memctl->memc_br0 = (CONFIG_SYS_FLASH_BASE & BR_BA_MSK) | BR_MS_GPCM | BR_V;

	/* Re-do sizing to get full correct info */
	size_b0 = flash_get_size((vu_long *)CONFIG_SYS_FLASH_BASE, &flash_info[0]);

	flash_get_offsets (CONFIG_SYS_FLASH_BASE, &flash_info[0]);

#if CONFIG_SYS_MONITOR_BASE >= CONFIG_SYS_FLASH_BASE
	/* monitor protection ON by default */
	flash_protect(FLAG_PROTECT_SET,
		      CONFIG_SYS_MONITOR_BASE,
		      CONFIG_SYS_MONITOR_BASE+monitor_flash_len-1,
		      &flash_info[0]);
#endif

#ifdef	CONFIG_ENV_IS_IN_FLASH
	/* ENV protection ON by default */
	flash_protect(FLAG_PROTECT_SET,
		      CONFIG_ENV_ADDR,
		      CONFIG_ENV_ADDR+CONFIG_ENV_SIZE-1,
		      &flash_info[0]);
#endif

	if (size_b1) {
		memctl->memc_or1 = CONFIG_SYS_OR_TIMING_FLASH | (-size_b1 & 0xFFFF8000);
		memctl->memc_br1 = ((CONFIG_SYS_FLASH_BASE + size_b0) & BR_BA_MSK) |
				    BR_MS_GPCM | BR_V;

		/* Re-do sizing to get full correct info */
		size_b1 = flash_get_size((vu_long *)(CONFIG_SYS_FLASH_BASE + size_b0),
					  &flash_info[1]);

		flash_get_offsets (CONFIG_SYS_FLASH_BASE + size_b0, &flash_info[1]);

#if CONFIG_SYS_MONITOR_BASE >= CONFIG_SYS_FLASH_BASE
		/* monitor protection ON by default */
		flash_protect(FLAG_PROTECT_SET,
			      CONFIG_SYS_MONITOR_BASE,
			      CONFIG_SYS_MONITOR_BASE+monitor_flash_len-1,
			      &flash_info[1]);
#endif

#ifdef	CONFIG_ENV_IS_IN_FLASH
		/* ENV protection ON by default */
		flash_protect(FLAG_PROTECT_SET,
			      CONFIG_ENV_ADDR,
			      CONFIG_ENV_ADDR+CONFIG_ENV_SIZE-1,
			      &flash_info[1]);
#endif
	} else {
		memctl->memc_br1 = 0;		/* invalidate bank */

		flash_info[1].flash_id = FLASH_UNKNOWN;
		flash_info[1].sector_count = -1;
	}

	flash_info[0].size = size_b0;
	flash_info[1].size = size_b1;


#endif  /* CONFIG_BOOT_32B */

	return (size_b0 + size_b1);
}
#if 0
/*-----------------------------------------------------------------------
 */
static void flash_get_offsets (ulong base, flash_info_t *info)
{
	int i;

	/* set up sector start address table */
	if (info->flash_id & FLASH_BTYPE) {
		/* set sector offsets for bottom boot block type	*/
		info->start[0] = base + 0x00000000;
		info->start[1] = base + 0x00008000;
		info->start[2] = base + 0x0000C000;
		info->start[3] = base + 0x00010000;
		for (i = 4; i < info->sector_count; i++) {
			info->start[i] = base + (i * 0x00020000) - 0x00060000;
		}
	} else {
		/* set sector offsets for top boot block type		*/
		i = info->sector_count - 1;
		info->start[i--] = base + info->size - 0x00008000;
		info->start[i--] = base + info->size - 0x0000C000;
		info->start[i--] = base + info->size - 0x00010000;
		for (; i >= 0; i--) {
			info->start[i] = base + i * 0x00020000;
		}
	}
}
#endif
/*-----------------------------------------------------------------------
 */
void flash_print_info  (flash_info_t *info)
{
	int i;

	if (info->flash_id == FLASH_UNKNOWN) {
		printf ("missing or unknown FLASH type\n");
		return;
	}

	switch (info->flash_id & FLASH_VENDMASK) {
	case FLASH_MAN_AMD:	printf ("AMD ");		break;
	case FLASH_MAN_FUJ:	printf ("FUJITSU ");		break;
	default:		printf ("Unknown Vendor ");	break;
	}

	switch (info->flash_id & FLASH_TYPEMASK) {
	case FLASH_AM400B:	printf ("AM29LV400B (4 Mbit, bottom boot sect)\n");
				break;
	case FLASH_AM400T:	printf ("AM29LV400T (4 Mbit, top boot sector)\n");
				break;
	case FLASH_AM800B:	printf ("AM29LV800B (8 Mbit, bottom boot sect)\n");
				break;
	case FLASH_AM800T:	printf ("AM29LV800T (8 Mbit, top boot sector)\n");
				break;
	case FLASH_AM160B:	printf ("AM29LV160B (16 Mbit, bottom boot sect)\n");
				break;
	case FLASH_AM160T:	printf ("AM29LV160T (16 Mbit, top boot sector)\n");
				break;
	case FLASH_AM320B:	printf ("AM29LV320B (32 Mbit, bottom boot sect)\n");
				break;
	case FLASH_AM320T:	printf ("AM29LV320T (32 Mbit, top boot sector)\n");
				break;
	default:		printf ("Unknown Chip Type\n");
				break;
	}

	printf ("  Size: %ld MB in %d Sectors\n",
		info->size >> 20, info->sector_count);

	printf ("  Sector Start Addresses:");
	for (i=0; i<info->sector_count; ++i) {
		if ((i % 5) == 0)
			printf ("\n   ");
		printf (" %08lX%s",
			info->start[i],
			info->protect[i] ? " (RO)" : "     "
		);
	}
	printf ("\n");
	return;
}

/*-----------------------------------------------------------------------
 */


/*-----------------------------------------------------------------------
 */

/*
 * The following code cannot be run from FLASH!
 */
#if 0
static ulong flash_get_size (vu_long *addr, flash_info_t *info)
{
	short i;
	ulong value;
	ulong base = (ulong)addr;

	/* Write auto select command: read Manufacturer ID */
	addr[0x0555] = 0x00AA00AA;
	addr[0x02AA] = 0x00550055;
	addr[0x0555] = 0x00900090;

	value = addr[0];

	switch (value) {
	case AMD_MANUFACT:
		info->flash_id = FLASH_MAN_AMD;
		break;
	case FUJ_MANUFACT:
		info->flash_id = FLASH_MAN_FUJ;
		break;
	default:
		info->flash_id = FLASH_UNKNOWN;
		info->sector_count = 0;
		info->size = 0;
		return (0);			/* no or unknown flash	*/
	}

	value = addr[1];			/* device ID		*/

	switch (value) {
	case AMD_ID_LV400T:
		info->flash_id += FLASH_AM400T;
		info->sector_count = 11;
		info->size = 0x00100000;
		break;				/* => 1 MB		*/

	case AMD_ID_LV400B:
		info->flash_id += FLASH_AM400B;
		info->sector_count = 11;
		info->size = 0x00100000;
		break;				/* => 1 MB		*/

	case AMD_ID_LV800T:
		info->flash_id += FLASH_AM800T;
		info->sector_count = 19;
		info->size = 0x00200000;
		break;				/* => 2 MB		*/

	case AMD_ID_LV800B:
		info->flash_id += FLASH_AM800B;
		info->sector_count = 19;
		info->size = 0x00200000;
		break;				/* => 2 MB		*/

	case AMD_ID_LV160T:
		info->flash_id += FLASH_AM160T;
		info->sector_count = 35;
		info->size = 0x00400000;
		break;				/* => 4 MB		*/

	case AMD_ID_LV160B:
		info->flash_id += FLASH_AM160B;
		info->sector_count = 35;
		info->size = 0x00400000;
		break;				/* => 4 MB		*/
#if 0	/* enable when device IDs are available */
	case AMD_ID_LV320T:
		info->flash_id += FLASH_AM320T;
		info->sector_count = 67;
		info->size = 0x00800000;
		break;				/* => 8 MB		*/

	case AMD_ID_LV320B:
		info->flash_id += FLASH_AM320B;
		info->sector_count = 67;
		info->size = 0x00800000;
		break;				/* => 8 MB		*/
#endif
	default:
		info->flash_id = FLASH_UNKNOWN;
		return (0);			/* => no or unknown flash */
	}

	/* set up sector start address table */
	if (info->flash_id & FLASH_BTYPE) {
		/* set sector offsets for bottom boot block type	*/
		info->start[0] = base + 0x00000000;
		info->start[1] = base + 0x00008000;
		info->start[2] = base + 0x0000C000;
		info->start[3] = base + 0x00010000;
		for (i = 4; i < info->sector_count; i++) {
			info->start[i] = base + (i * 0x00020000) - 0x00060000;
		}
	} else {
		/* set sector offsets for top boot block type		*/
		i = info->sector_count - 1;
		info->start[i--] = base + info->size - 0x00008000;
		info->start[i--] = base + info->size - 0x0000C000;
		info->start[i--] = base + info->size - 0x00010000;
		for (; i >= 0; i--) {
			info->start[i] = base + i * 0x00020000;
		}
	}

	/* check for protected sectors */
	for (i = 0; i < info->sector_count; i++) {
		/* read sector protection at sector address, (A7 .. A0) = 0x02 */
		/* D0 = 1 if protected */
		addr = (volatile unsigned long *)(info->start[i]);
		info->protect[i] = addr[2] & 1;
	}

	/*
	 * Prevent writes to uninitialized FLASH.
	 */
	if (info->flash_id != FLASH_UNKNOWN) {
		addr = (volatile unsigned long *)info->start[0];

		*addr = 0x00F000F0;	/* reset bank */
	}

	return (info->size);
}
#endif

/*-----------------------------------------------------------------------
 */

int	flash_erase (flash_info_t *info, int s_first, int s_last)
{
	vu_long *addr = (vu_long*)(info->start[0]);
	int flag, prot, sect, l_sect,in_mid,in_did;
	ulong start, now, last;

	if ((s_first < 0) || (s_first > s_last)) {
		if (info->flash_id == FLASH_UNKNOWN) {
			printf ("- missing\n");
		} else {
			printf ("- no sectors to erase\n");
		}
		return 1;
	}

	if ((info->flash_id == FLASH_UNKNOWN) ||
	    (info->flash_id > FLASH_AMD_COMP)) {
		printf ("Can't erase unknown flash type %08lx - aborted\n",
			info->flash_id);
		return 1;
	}

	prot = 0;
	for (sect=s_first; sect<=s_last; ++sect) {
		if (info->protect[sect]) {
			prot++;
		}
	}

	if (prot) {
		printf ("- Warning: %d protected sectors will not be erased!\n",
			prot);
	} else {
		printf ("\n");
	}

	l_sect = -1;

	/* Disable interrupts which might cause a timeout here */
	flag = disable_interrupts();
#if defined (CONFIG_BOOT_8B )
	my_out_8( (unsigned char * )  ((ulong)addr+0x555) , 0xaa );
	my_out_8( (unsigned char * )  ((ulong)addr+0x2aa) , 0x55 );
	my_out_8( (unsigned char * )  ((ulong)addr+0x555) , 0x90 );
	in_mid=my_in_8( (unsigned char * ) addr );
	in_did=my_in_8( (unsigned char * ) ((ulong)addr+1) );
	printf(" man ID=0x%x, dev ID=0x%x.\n",in_mid,in_did );
	my_out_8( (unsigned char *)addr, 0xf0);
	udelay(1);
	my_out_8(     (unsigned char *) ((ulong)addr+0x555),0xaa );
	my_out_8(     (unsigned char *) ((ulong)addr+0x2aa),0x55 );
	my_out_8(     (unsigned char *) ((ulong)addr+0x555),0x80 );
	my_out_8(     (unsigned char *) ((ulong)addr+0x555),0xaa );
	my_out_8(     (unsigned char *) ((ulong)addr+0x2aa),0x55 );
	/* Start erase on unprotected sectors */
	for (sect = s_first; sect<=s_last; sect++) {
		if (info->protect[sect] == 0) {	/* not protected */
			addr = (vu_long*)(info->start[sect]);
			/*addr[0] = 0x00300030; */
			my_out_8(     (unsigned char *) ((ulong)addr),0x30 );
			l_sect = sect;
		}
	}
#elif defined(CONFIG_BOOT_16B )
	my_out_be16( (unsigned short * )  ((ulong)addr+ (0xaaa)) , 0xaa );
	my_out_be16( (unsigned short * )  ((ulong)addr+ (0x554)) , 0x55 );
	my_out_be16( (unsigned short * )  ((ulong)addr+ (0xaaa)) , 0x90 );
	in_mid=my_in_be16( (unsigned short * ) addr );
	in_did=my_in_be16 ( (unsigned short * ) ((ulong)addr+2) );
	printf(" man ID=0x%x, dev ID=0x%x.\n",in_mid,in_did );
	my_out_be16( (unsigned short *)addr, 0xf0);
	udelay(1);
	my_out_be16(     (unsigned short *) ((ulong)addr+ 0xaaa),0xaa );
	my_out_be16(     (unsigned short *) ((ulong)addr+0x554),0x55 );
	my_out_be16(     (unsigned short *) ((ulong)addr+0xaaa),0x80 );
	my_out_be16(     (unsigned short *) ((ulong)addr+0xaaa),0xaa );
	my_out_be16(     (unsigned short *) ((ulong)addr+0x554),0x55 );
	/* Start erase on unprotected sectors */
	for (sect = s_first; sect<=s_last; sect++) {
		if (info->protect[sect] == 0) {	/* not protected */
			addr = (vu_long*)(info->start[sect]);
			my_out_be16(     (unsigned short *) ((ulong)addr),0x30 );
			l_sect = sect;
		}
	}

#elif defined(CONFIG_BOOT_32B)
	my_out_be32( (unsigned * )  ((ulong)addr+0x1554) , 0xaa );
	my_out_be32( (unsigned * )  ((ulong)addr+0xaa8) , 0x55 );
	my_out_be32( (unsigned  *)  ((ulong)addr+0x1554) , 0x90 );
	in_mid=my_in_be32( (unsigned  * ) addr );
	in_did=my_in_be32( (unsigned  * ) ((ulong)addr+4) );
	printf(" man ID=0x%x, dev ID=0x%x.\n",in_mid,in_did );
	my_out_be32( (unsigned *)addr, 0xf0);
	udelay(1);
	my_out_be32(     (unsigned  *) ((ulong)addr+0x1554),0xaa );
	my_out_be32(     (unsigned  *) ((ulong)addr+0xaa8),0x55 );
	my_out_be32(     (unsigned  *) ((ulong)addr+0x1554),0x80 );
	my_out_be32(     (unsigned  *) ((ulong)addr+0x1554),0xaa );
	my_out_be32(     (unsigned  *) ((ulong)addr+0xaa8),0x55 );
	/* Start erase on unprotected sectors */
	for (sect = s_first; sect<=s_last; sect++) {
		if (info->protect[sect] == 0) {	/* not protected */
			addr = (vu_long*)(info->start[sect]);
			my_out_be32(     (unsigned *) ((ulong)addr),0x00300030 );
			l_sect = sect;
		}
	}

#else
# error CONFIG_BOOT_(size)B missing.
#endif
	/* re-enable interrupts if necessary */
	if (flag)
		enable_interrupts();

	/* wait at least 80us - let's wait 1 ms */
	udelay (1000);

	/*
	 * We wait for the last triggered sector
	 */
	if (l_sect < 0)
		goto DONE;

	start = get_timer (0);
	last  = start;
	addr = (vu_long*)(info->start[l_sect]);
#if defined (CONFIG_BOOT_8B)
	while (  (my_in_8((unsigned char *)addr) & 0x80) != 0x80 )
#elif defined(CONFIG_BOOT_16B )
	while (  (my_in_be16((unsigned short *)addr) & 0x0080) != 0x0080 )
#elif defined(CONFIG_BOOT_32B)
	while (  (my_in_be32((unsigned  *)addr) & 0x00800080) != 0x00800080 )
#else
# error CONFIG_BOOT_(size)B missing.
#endif
	{
		if ((now = get_timer(start)) > CONFIG_SYS_FLASH_ERASE_TOUT) {
			printf ("Timeout\n");
			return 1;
		}
		/* show that we're waiting */
		if ((now - last) > 1000) {	/* every second */
			putc ('.');
			last = now;
		}
	}
DONE:
	/* reset to read mode */
	addr = (volatile unsigned long *)info->start[0];
#if defined (CONFIG_BOOT_8B)
	my_out_8( (unsigned char *)addr, 0xf0);
#elif defined(CONFIG_BOOT_16B )
	my_out_be16( (unsigned short * ) addr , 0x00f0 );
#elif defined(CONFIG_BOOT_32B)
	my_out_be32 ( (unsigned *)addr,  0x00F000F0 );	/* reset bank */
#else
# error CONFIG_BOOT_(size)B missing.
#endif
	printf (" done\n");
	return 0;
}

/*-----------------------------------------------------------------------
 * Copy memory to flash, returns:
 * 0 - OK
 * 1 - write timeout
 * 2 - Flash not erased
 */

int write_buff (flash_info_t *info, uchar *src, ulong addr, ulong cnt)
{
	ulong cp, wp, data;
	int i, l, rc;

	wp = (addr & ~3);	/* get lower word aligned address */

	/*
	 * handle unaligned start bytes
	 */
	if ((l = addr - wp) != 0) {
		data = 0;
		for (i=0, cp=wp; i<l; ++i, ++cp) {
			data = (data << 8) | (*(uchar *)cp);
		}
		for (; i<4 && cnt>0; ++i) {
			data = (data << 8) | *src++;
			--cnt;
			++cp;
		}
		for (; cnt==0 && i<4; ++i, ++cp) {
			data = (data << 8) | (*(uchar *)cp);
		}

		if ((rc = write_word(info, wp, data)) != 0) {
			return (rc);
		}
		wp += 4;
	}

	/*
	 * handle word aligned part
	 */
	while (cnt >= 4) {
		data = 0;
		for (i=0; i<4; ++i) {
			data = (data << 8) | *src++;
		}
		if ((rc = write_word(info, wp, data)) != 0) {
			return (rc);
		}
		wp  += 4;
		cnt -= 4;
	}

	if (cnt == 0) {
		return (0);
	}

	/*
	 * handle unaligned tail bytes
	 */
	data = 0;
	for (i=0, cp=wp; i<4 && cnt>0; ++i, ++cp) {
		data = (data << 8) | *src++;
		--cnt;
	}
	for (; i<4; ++i, ++cp) {
		data = (data << 8) | (*(uchar *)cp);
	}

	return (write_word(info, wp, data));
}

/*-----------------------------------------------------------------------
 * Write a word to Flash, returns:
 * 0 - OK
 * 1 - write timeout
 * 2 - Flash not erased
 */
static int write_word (flash_info_t *info, ulong dest, ulong data)
{
	ulong addr = (ulong)(info->start[0]);
	ulong start,last;
	int flag;
	ulong i;
	int  data_short[2];

	/* Check if Flash is (sufficiently) erased */
	if ( ((ulong)  *(ulong *)dest & data) != data ) {
		return (2);
	}
	/* Disable interrupts which might cause a timeout here */
	flag = disable_interrupts();
#if defined(CONFIG_BOOT_8B)
#ifdef DEBUG
	{
	int in_mid,in_did;
	my_out_8( (unsigned char * )  (addr+0x555) , 0xaa );
	my_out_8( (unsigned char * )  (addr+0x2aa) , 0x55 );
	my_out_8( (unsigned char * )  (addr+0x555) , 0x90 );
	in_mid=my_in_8( (unsigned char * ) addr );
	in_did=my_in_8( (unsigned char * ) (addr+1) );
	printf(" man ID=0x%x, dev ID=0x%x.\n",in_mid,in_did );
	my_out_8( (unsigned char *)addr, 0xf0);
	udelay(1);
	}
#endif
      {
	int  data_ch[4];
	data_ch[0]=(int ) ((data>>24) & 0xff);
	data_ch[1]=(int ) ((data>>16) &0xff );
	data_ch[2]=(int ) ((data >>8) & 0xff);
	data_ch[3]=(int ) (data & 0xff);
	for (i=0;i<4;i++ ){
	  my_out_8( (unsigned char *) (addr+0x555),0xaa);
	  my_out_8((unsigned char *) (addr+0x2aa),0x55);
	  my_out_8( (unsigned char *)  (addr+0x555),0xa0);
	  my_out_8((unsigned char *)  (dest+i) ,data_ch[i]);
	/* re-enable interrupts if necessary */
	if (flag)
		enable_interrupts();

	  start = get_timer (0);
	last  = start;
	  while(  ( my_in_8((unsigned char *) (dest+i)) ) != ( data_ch[i]  ) ) {
		  if (get_timer(start) > CONFIG_SYS_FLASH_WRITE_TOUT ) {
			  return 1;
		  }
	  }
	}/* for */
     }
#elif defined( CONFIG_BOOT_16B)
	data_short[0]=(int) (data>>16) & 0xffff;
	data_short[1]=(int ) data & 0xffff ;
	for (i=0;i<2;i++ ){
	my_out_be16(     (unsigned short *) ((ulong)addr+ 0xaaa),0xaa );
	my_out_be16(     (unsigned short *) ((ulong)addr+ 0x554),0x55 );
	my_out_be16(     (unsigned short *) ((ulong)addr+ 0xaaa),0xa0 );
	my_out_be16(  (unsigned short *) (dest+(i*2)) ,data_short[i]);
	/* re-enable interrupts if necessary */
	if (flag)
		enable_interrupts();
	  start = get_timer (0);
	last  = start;
	  while(  ( my_in_be16((unsigned short *) (dest+(i*2))) ) != ( data_short[i]  ) ) {
		  if (get_timer(start) > CONFIG_SYS_FLASH_WRITE_TOUT ) {
			  return 1;
		  }
	  }
	}
#elif defined( CONFIG_BOOT_32B)
	addr[0x0555] = 0x00AA00AA;
	addr[0x02AA] = 0x00550055;
	addr[0x0555] = 0x00A000A0;

	*((vu_long *)dest) = data;

	/* re-enable interrupts if necessary */
	if (flag)
		enable_interrupts();

	/* data polling for D7 */
	start = get_timer (0);
	while ((*((vu_long *)dest) & 0x00800080) != (data & 0x00800080)) {
		if (get_timer(start) > CONFIG_SYS_FLASH_WRITE_TOUT) {
			return (1);
		}
	}
#endif


	return (0);
}
#ifdef  CONFIG_BOOT_8B
static int my_in_8  ( unsigned char *addr)
{
       int ret;
       __asm__ __volatile__("lbz%U1%X1 %0,%1; eieio" : "=r" (ret) : "m" (*addr));
       return ret;
}

static void my_out_8  ( unsigned char *addr, int val)
{
       __asm__ __volatile__("stb%U0%X0 %1,%0; eieio" : "=m" (*addr) : "r" (val));
}
#endif
#ifdef  CONFIG_BOOT_16B
static int my_in_be16( unsigned short *addr)
{
       int ret;
	__asm__ __volatile__("lhz%U1%X1 %0,%1; eieio" : "=r" (ret) : "m" (*addr));
				return ret;
}
static void my_out_be16( unsigned short *addr, int val)
{
       __asm__ __volatile__("sth%U0%X0 %1,%0; eieio" : "=m" (*addr) : "r" (val));
}
#endif
#ifdef  CONFIG_BOOT_32B
static  unsigned my_in_be32( unsigned *addr)
{
	unsigned ret;
	__asm__ __volatile__("lwz%U1%X1 %0,%1; eieio" : "=r" (ret) : "m" (*addr));
				return ret;
}
static  void my_out_be32( unsigned *addr, int val)
{
       __asm__ __volatile__("stw%U0%X0 %1,%0; eieio" : "=m" (*addr) : "r" (val));
}
#endif